From 61022f3817dc7bc4d7b75d5e948b838ea0c5edc1 Mon Sep 17 00:00:00 2001 From: Yang Tse Date: Fri, 20 Apr 2007 00:07:19 +0000 Subject: - Save one call to curlx_tvnow(), which calls gettimeofday(), in each of Curl_socket_ready(), Curl_poll() and Curl_select() when these are called with a zero timeout or a timeout value indicating a blocking call should be performed. These unnecessary calls to gettimeofday() got introduced in 7.16.2 when fixing 'timeout would restart when signal caught while awaiting socket events' on 20 March 2007. - Move some loop breaking logic from the while clause into the loop, avoiding compiler warning 'assignment within conditional expression' --- lib/select.c | 160 +++++++++++++++++++++++++++++++++++++++++++++++------------ 1 file changed, 127 insertions(+), 33 deletions(-) (limited to 'lib/select.c') diff --git a/lib/select.c b/lib/select.c index 30aece461..9d75e77dd 100644 --- a/lib/select.c +++ b/lib/select.c @@ -76,12 +76,12 @@ #define elapsed_ms (int)curlx_tvdiff(curlx_tvnow(), initial_tv) #ifdef CURL_ACKNOWLEDGE_EINTR -#define error_not_EINTR (error != EINTR) +#define error_is_EINTR (error == EINTR) #else -#define error_not_EINTR (1) +#define error_is_EINTR (0) #endif -#define SMALL_POLLNFDS 0X20 +#define SMALL_POLLNFDS 0x20 /* * Internal function used for waiting a specific amount of ms @@ -136,9 +136,15 @@ static int wait_ms(int timeout_ms) pending_tv.tv_usec = (pending_ms % 1000) * 1000; r = select(0, NULL, NULL, NULL, &pending_tv); #endif /* HAVE_POLL_FINE */ - } while ((r == -1) && (error = SOCKERRNO) && - (error != EINVAL) && error_not_EINTR && - ((pending_ms = timeout_ms - elapsed_ms) > 0)); + if (r != -1) + break; + error = SOCKERRNO; + if ((error == EINVAL) || error_is_EINTR) + break; + pending_ms = timeout_ms - elapsed_ms; + if (pending_ms <= 0) + break; + } while (r == -1); #endif /* USE_WINSOCK */ if (r) r = -1; @@ -188,8 +194,15 @@ int Curl_socket_ready(curl_socket_t readfd, curl_socket_t writefd, return r; } - pending_ms = timeout_ms; - initial_tv = curlx_tvnow(); + /* Avoid initial timestamp, avoid gettimeofday() call, when elapsed + time in this function does not need to be measured. This happens + when function is called with a zero timeout or a negative timeout + value indicating a blocking call should be performed. */ + + if (timeout_ms > 0) { + pending_ms = timeout_ms; + initial_tv = curlx_tvnow(); + } #ifdef HAVE_POLL_FINE @@ -210,10 +223,20 @@ int Curl_socket_ready(curl_socket_t readfd, curl_socket_t writefd, do { if (timeout_ms < 0) pending_ms = -1; + else if (!timeout_ms) + pending_ms = 0; r = poll(pfd, num, pending_ms); - } while ((r == -1) && (error = SOCKERRNO) && - (error != EINVAL) && error_not_EINTR && - ((timeout_ms < 0) || ((pending_ms = timeout_ms - elapsed_ms) > 0))); + if (r != -1) + break; + error = SOCKERRNO; + if ((error == EINVAL) || error_is_EINTR) + break; + if (timeout_ms > 0) { + pending_ms = timeout_ms - elapsed_ms; + if (pending_ms <= 0) + break; + } + } while (r == -1); if (r < 0) return -1; @@ -263,14 +286,26 @@ int Curl_socket_ready(curl_socket_t readfd, curl_socket_t writefd, ptimeout = (timeout_ms < 0) ? NULL : &pending_tv; do { - if (ptimeout) { + if (timeout_ms > 0) { pending_tv.tv_sec = pending_ms / 1000; pending_tv.tv_usec = (pending_ms % 1000) * 1000; } + else if (!timeout_ms) { + pending_tv.tv_sec = 0; + pending_tv.tv_usec = 0; + } r = select((int)maxfd + 1, &fds_read, &fds_write, &fds_err, ptimeout); - } while ((r == -1) && (error = SOCKERRNO) && - (error != EINVAL) && (error != EBADF) && error_not_EINTR && - ((timeout_ms < 0) || ((pending_ms = timeout_ms - elapsed_ms) > 0))); + if (r != -1) + break; + error = SOCKERRNO; + if ((error == EINVAL) || (error == EBADF) || error_is_EINTR) + break; + if (timeout_ms > 0) { + pending_ms = timeout_ms - elapsed_ms; + if (pending_ms <= 0) + break; + } + } while (r == -1); if (r < 0) return -1; @@ -343,18 +378,35 @@ int Curl_poll(struct pollfd ufds[], unsigned int nfds, int timeout_ms) return r; } - pending_ms = timeout_ms; - initial_tv = curlx_tvnow(); + /* Avoid initial timestamp, avoid gettimeofday() call, when elapsed + time in this function does not need to be measured. This happens + when function is called with a zero timeout or a negative timeout + value indicating a blocking call should be performed. */ + + if (timeout_ms > 0) { + pending_ms = timeout_ms; + initial_tv = curlx_tvnow(); + } #ifdef HAVE_POLL_FINE do { if (timeout_ms < 0) pending_ms = -1; + else if (!timeout_ms) + pending_ms = 0; r = poll(ufds, nfds, pending_ms); - } while ((r == -1) && (error = SOCKERRNO) && - (error != EINVAL) && error_not_EINTR && - ((timeout_ms < 0) || ((pending_ms = timeout_ms - elapsed_ms) > 0))); + if (r != -1) + break; + error = SOCKERRNO; + if ((error == EINVAL) || error_is_EINTR) + break; + if (timeout_ms > 0) { + pending_ms = timeout_ms - elapsed_ms; + if (pending_ms <= 0) + break; + } + } while (r == -1); #else /* HAVE_POLL_FINE */ @@ -384,14 +436,26 @@ int Curl_poll(struct pollfd ufds[], unsigned int nfds, int timeout_ms) ptimeout = (timeout_ms < 0) ? NULL : &pending_tv; do { - if (ptimeout) { + if (timeout_ms > 0) { pending_tv.tv_sec = pending_ms / 1000; pending_tv.tv_usec = (pending_ms % 1000) * 1000; } + else if (!timeout_ms) { + pending_tv.tv_sec = 0; + pending_tv.tv_usec = 0; + } r = select((int)maxfd + 1, &fds_read, &fds_write, &fds_err, ptimeout); - } while ((r == -1) && (error = SOCKERRNO) && - (error != EINVAL) && (error != EBADF) && error_not_EINTR && - ((timeout_ms < 0) || ((pending_ms = timeout_ms - elapsed_ms) > 0))); + if (r != -1) + break; + error = SOCKERRNO; + if ((error == EINVAL) || (error == EBADF) || error_is_EINTR) + break; + if (timeout_ms > 0) { + pending_ms = timeout_ms - elapsed_ms; + if (pending_ms <= 0) + break; + } + } while (r == -1); if (r < 0) return -1; @@ -481,8 +545,16 @@ int Curl_select(int nfds, return r; } - pending_ms = timeout_ms; - initial_tv = curlx_tvnow(); + /* Avoid initial timestamp, avoid gettimeofday() call, when elapsed + time in this function does not need to be measured. This happens + when function is called with a zero timeout in the timeval struct + referenced argument or when a NULL pointer is received as timeval + reference indicating a blocking call should be performed. */ + + if (timeout_ms > 0) { + pending_ms = timeout_ms; + initial_tv = curlx_tvnow(); + } #ifdef HAVE_POLL_FINE @@ -530,10 +602,20 @@ int Curl_select(int nfds, do { if (timeout_ms < 0) pending_ms = -1; + else if (!timeout_ms) + pending_ms = 0; r = poll(poll_fds, poll_nfds, pending_ms); - } while ((r == -1) && (error = SOCKERRNO) && - (error != EINVAL) && error_not_EINTR && - ((timeout_ms < 0) || ((pending_ms = timeout_ms - elapsed_ms) > 0))); + if (r != -1) + break; + error = SOCKERRNO; + if ((error == EINVAL) || error_is_EINTR) + break; + if (timeout_ms > 0) { + pending_ms = timeout_ms - elapsed_ms; + if (pending_ms <= 0) + break; + } + } while (r == -1); if (r < 0) ret = -1; @@ -583,14 +665,26 @@ int Curl_select(int nfds, ptimeout = (timeout_ms < 0) ? NULL : &pending_tv; do { - if (ptimeout) { + if (timeout_ms > 0) { pending_tv.tv_sec = pending_ms / 1000; pending_tv.tv_usec = (pending_ms % 1000) * 1000; } + else if (!timeout_ms) { + pending_tv.tv_sec = 0; + pending_tv.tv_usec = 0; + } r = select(nfds, fds_read, fds_write, fds_excep, ptimeout); - } while ((r == -1) && (error = SOCKERRNO) && - (error != EINVAL) && (error != EBADF) && error_not_EINTR && - ((timeout_ms < 0) || ((pending_ms = timeout_ms - elapsed_ms) > 0))); + if (r != -1) + break; + error = SOCKERRNO; + if ((error == EINVAL) || (error == EBADF) || error_is_EINTR) + break; + if (timeout_ms > 0) { + pending_ms = timeout_ms - elapsed_ms; + if (pending_ms <= 0) + break; + } + } while (r == -1); if (r < 0) ret = -1; -- cgit v1.2.3